Field of the Invention
The present invention is directed to a signal conversion circuit and, more particularly, to an apparatus, system and method for converting thermal printhead dot history control signals from one type to a different type.
Description of the Background
Typical printers may be classified into four major categories: dot matrix printers, inkjet printers, laser printers, and thermal sublimation (or thermal transfer) printers. Thermal printers have become increasingly popular due to their economical performance. A thermal printer uses a thermal print head (TPH) to heat ribbons or paper containing dyes. The dyes of the heated ribbon are transferred onto the object to be printed or change the dye in the paper dark or a color (usually black).
More specifically, a TPH may print on an output medium by, for example, transferring pigment from a donor sheet to the output medium or by initiating a color-forming reaction in the output medium. The output medium may be a porous receiver receptive to the transferred pigment, or a paper coated with the color-forming chemistry, for example. Each of the TPHs, when activated, may form color on the medium passing underneath the TPH, creating a spot having a particular density. Regions with larger or denser spots are perceived as darker than regions with smaller or less dense spots. Digital images are rendered as two-dimensional arrays of very small and closely-spaced spots.
Furthermore, TPHs may be expensive and unique to particular manufacturers and printer models. In particular, various TPH manufacturers may produce TPHs capable of using dot history control (DHC) for which specific integrated circuit drivers (ICs) are used to control signal timing from the printer to the TPH. By producing THPs with unique ICs matched to specific models and brands of printers, THP manufacturers severely limit the constituent parts used to make a TPH to be used with a particular printer.
Thus, the need exists for an apparatus, system and method to allow for interchangeable and compatible integrated circuit drivers for thermal print heads and related apparatuses to solve the above-mentioned problems.